Email, Alfred Blumstein, J. Erik Jonsson University Professor of Urban Systems and Operations Research, Heinz College, Carnegie Mellon University, Jan. 22, 2015

On 1/22/2015 1:08 PM, Selby, Gardner (CMG-Austin) wrote:

Professor Blumstein:

Thanks to you for calling Friday. I am digesting your thoughts on crime in Texas.

I am hoping too you can help me understand the total crime index because it looks to me – and perhaps I’m wrong – like the FBI stopped declaring a total crime index some years ago. So how did Texas come up with one and should it be discounted?

Here is what I saw on this FBI web page: “In June 2004, the CJIS APB approved discontinuing the use of the Crime Index in the UCR Program and its publications, and it directed the FBI to publish a violent crime total and a property crime total. The Crime Index, first published in Crime in the United  States in 1960, was the title used for a simple aggregation of the seven main offense classifications (Part I offenses) in the SRS. The Modified Crime Index was the number of Crime Index offenses plus arson.

For several years, the CJIS Division studied the appropriateness and usefulness of these indices and brought the matter before many advisory groups including the UCR Subcommittee of the CJIS APB, the ASUCRP, and a meeting of leading criminologists and sociologists hosted by the BJS. In short, the Crime Index and the Modified Crime Index were not true indicators of the degrees of criminality because they were always driven upward by the offense with the highest number, typically larceny-theft. The sheer volume of those offenses overshadowed more serious but less frequently committed offenses, creating a bias against a jurisdiction with a high number of larceny-thefts but a low number of other serious crimes such as murder and forcible rape.”

??

g.

W. Gardner Selby

Reporter / News

Austin American-Statesman

PolitiFact Texas

2:30 p.m.

Jan. 22, 2015

The Crime Index was the sum of he seven crime numbers (4 violent crimes: M, R, FR, AA; and 3 property crimes: B, L, MVT), and that was criticized for the reasons they stated re larceny - large numbers of minor crimes dominate the Index. So they stopped doing that and replaced it with two numbers: Violent Crime and Property Crime. But those two numbers (no longer called "indexes", but calculated similarly) have many of the same properties. The Violet Crime total (1.16 million) includes 14,000 murders, but those are dominated by the 700,000 agg assaults. (Now you know why I want to separate out the murders and robberies, which are well defined and well reported) Similarly, the Property Crime total of 8.6 million includes 6 million larcenies but only 700,000 motor-vehicle thefts. Now this is better than having to deal with the sum of PC and VC, which is the 9.8 million "Index Crimes", but I would much prefer dealing with the 7 individual crime types, which are much more homogeneous internally and 7 numbers are certainly not unreasonable to manage - except in a headline.

...

Alfred Blumstein

Heinz College

Carnegie Mellon University

Pittsburgh, PA